ARRIS TM602G/115 Replacement Battery 7.4V 2200mAh BPB022S

ARRIS TM602G/115 Series — 7.4V Li-ion Replacement Battery (BPB022S)

This is a 7.4V, 2200mAh Li-ion replacement battery for the ARRIS TM602G/115 cable modem and a broad range of compatible ARRIS modem-router units. It slots into the modem's backup bay and keeps the unit running when mains power drops. Fits TM602G/115, TM02AC1G6, TM822G, TG862G, and 23 additional ARRIS models sharing the same connector and BMS protocol.

• Multi-model fit — TM602G/115 through TM822G: These ARRIS units share a common 7.4V battery bay, the same JST-style connector, and a firmware-level BMS handshake. The modem's power management circuit recognises cell voltage and communicates charge state through the same protocol across the range.
• Bench tested on actual hardware: We ran this cell on a TM822G and confirmed the modem accepted the BMS handshake within the first charge cycle. The protection circuit triggered correctly at low-voltage cutoff and the modem reported battery status accurately in its admin interface.
• First-charge cycle on cable modem backup batteries: After installing, leave the modem plugged in for at least 4 hours before testing backup function. ARRIS modem firmware gates emergency power use on a completed charge cycle — the modem will not draw from the battery during an outage until that cycle is logged.

Battery self-test failing after swap on TM602G/115

ARRIS modems run an automated battery self-test that checks cell voltage and BMS response against firmware thresholds. A freshly installed cell may sit at storage voltage — typically around 3.7V per cell — which reads below the modem's pass threshold. The modem will log a self-test failure and may flag the battery LED amber or red. Allow a full 4-hour charge to bring both cells to 4.1–4.2V each before the firmware will clear the fault.

VoIP calls dropping during outage while internet stays up

During a power outage, some ARRIS units prioritise the data path and reduce power delivery to the telephony processor under load. If the backup battery is not fully charged, the sustained current needed for active VoIP calls causes voltage to sag below the telephony circuit's operating floor while the data side stays alive. This is not a modem fault — it is a power-budget behaviour tied to battery state of charge. Charge the battery fully before the next outage event; the telephony processor requires the cell to hold above 7.0V under load.